Cross correlations and the nuclear Overhauser effect of 13C nuclei in rotating methyl groups

Abstract Isotopically labeled methyl groups provide NMR probes in large, otherwise deuterated proteins. However, the resonance assignment constitutes a bottleneck for broader applicability of methyl-based NMR. Here, we present the automated MethylFLYA method for the assignment of methyl groups that is based on methyl-methyl nuclear Overhauser effect spectroscopy (NOESY) peak lists. MethylFLYA is applied to five proteins (28–358 kDa) comprising a total of 708 isotope-labeled methyl groups, of which 612 contribute NOESY cross peaks. MethylFLYA confidently assigns 488 methyl groups, i.e. 80% of those with NOESY data. Of these, 459 agree with the reference, 6 were different, and 23 were without reference assignment. MethylFLYA assigns significantly more methyl groups than alternative algorithms, has an average error rate of 1%, modest runtimes of 0.4–1.2 h, and can handle arbitrary isotope labeling patterns and data from other types of NMR spectra.

Download Full-text

1H NMR studies of [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in dimethylsulfoxide by nuclear Overhauser effect (NOE) enhancement spectroscopy: cis-trans Isomerism of the His-Pro bond

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19901106 ◽

1990 ◽

Vol 55 (4) ◽

pp. 1106-1111 ◽

Cited By ~ 1

Author(s):

John Matsoukas ◽

Paul Cordopatis ◽

Raghav Yamdagni ◽

Graham J. Moore

Keyword(s):

1H Nmr ◽

Nuclear Overhauser Effect ◽

Nmr Studies ◽

Restricted Rotation ◽

Overhauser Effect ◽

Major Isomer ◽

Conformational Properties ◽

Nuclear Overhauser

The conformational properties of the Sarmesin analogues [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in hexadeutero-dimethysulfoxide were investigated by Nuclear Overhauser Effect (NOE) Enhancement Studies. Cis-trans isomers (ratio 1 : 6) due to restricted rotation of the His-Pro bond were observed. Interresidue interactions between the His Cα proton and the two Pro Cδ protons revealed that the major isomer was the trans.

Download Full-text

Cylindromicin from Arctic-Derived Fungus Tolypocladium sp. SCSIO 40433

Molecules ◽

10.3390/molecules26041080 ◽

2021 ◽

Vol 26 (4) ◽

pp. 1080

Author(s):

Imran Khan ◽

Jing Peng ◽

Zhuangjie Fang ◽

Wei Liu ◽

Wenjun Zhang ◽

...

Keyword(s):

Secondary Metabolites ◽

Nuclear Overhauser Effect ◽

Inhibition Activity ◽

Tyrosinase Inhibition ◽

Bioactive Natural Products ◽

Chemical Structures ◽

Overhauser Effect ◽

Spectroscopic Analyses ◽

Potential Resource ◽

Nuclear Overhauser

The fungus strain SCSIO 40433 was isolated from an Arctic-derived glacier sediment sample and characterized as Tolypocladium cylindrosporum. A new compound, cylindromicin (1), and seven known secondary metabolites (2–8) were isolated from this strain. The chemical structures of these compounds were elucidated by comprehensive spectroscopic analyses. Cylindromicin (1) featured a 3,4-dihydro-2H-pyran skeleton. The absolute configuration of compound 1 was assigned via interpretation of key Nuclear Overhauser Effect Spectroscopy (NOESY) correlations and Electronic Circular Dichroism (ECD) calculation. Cylindromicin (1) exhibited significant tyrosinase inhibition activity. This study highlights Polar fungi as a potential resource for new bioactive natural products.

Download Full-text